大跨度空腹式连续刚构桥设计理论与方法

为寻求常规连续刚构桥适用跨径和斜拉桥适用跨径之间的合理、经济桥型,在常规连续刚构桥的基础上结合拱桥的力学特点提出空腹式连续刚构桥型。该桥型在常规连续刚构桥的形式上加大箱梁根部高度,并对箱梁根部的腹板进行挖空,减轻自重,形成梁-拱组合力学效应,从而提高结构承载效率,增强桥梁跨越能力。空腹式连续刚构桥可布置为单主跨、多主跨以及单T的形式,也可与常规连续刚构组合,桥墩可采用双肢薄壁墩或箱形柱式墩。采用正交试验法对该桥型关键结构参数进行研究,并根据实际工程对总体结构参数取值提出建议。该桥型采用平衡悬臂方法施工,工程造价指标、运营维护技术要求及费用与常规连续刚构桥相当,适用跨径在200~400 m,可望填补常规连续刚构桥适用跨径和斜拉桥适用跨径之间的空白。

Design Theories and Methods for Long-Span Open-Web Continuous Rigid-Frame Bridge

To find a rational and economical bridge type that has the spanning ability between the conventional continuous rigid-frame bridge and cable-stayed bridge,the open-web continuous rigid-frame bridge is proposed,which absorbs the structural features of conventional continuous rigid-frame bridge and the mechanical property of arch bridge.On the basis of the structural configuration of the conventional continuous rigid frame bridge,the depth of the box girder at the support are increased,and the webs there are hollowed out to reduce the self weight of the box girder,thus to generate a girder-arch synergetic load-bearing effect,and as a result,the load bearing efficiency of the structure is improved and the spanning ability of the bridge is enhanced.The open-web continuous rigid-frame bridge can incorporate a single main span or multiple main spans,adopt the single T-shaped main girder and merge with the conventional continuous rigid-frame structure.The thin-walled piers or the box-section column piers are all applicable.The orthogonal experiment method is used to study the key structural parameters of the bridge of such type,and the parameter values of the overall bridge are given in accordance with the actual engineering practices.This type of bridge can be constructed by the balanced cantilever method,with the indexes of costs,technical demands for operation and maintenance and fees are approximate to those of the conventional continuous rigid-frame bridge.The proper spanning lengths for the open-web continuous rigid-frame bridge are within the range of 200 to 400 m,which is expected to be an option between the conventional continuous rigid-frame bridge and the cable-stayed bridge.